1) The DDL script doesn't include the DROP statements like Sql Server generation template does
2) The DDL script has one slash symbol after any CREATE TABLE statement. When I execute the DDL script using SQLPlus I receive ORA-00955 error after the each CREATE TABLE statement

We have added DROP statements as a part of our Generate Database From Model wizard support.
More information about the new features is avalable here.
The latest 5.70.190 build is available in Registered Users' Area.